The model is based on Mapleson's Model P for inhaled anaesthetics, but has compartments for lungs, peripheral shunt, kidneys, portal bed, liver, other viscera, muscle, other lean, fat, brain, i.m. injection site and for various blood "pools". Intracellular and extracellular fluids are represented separately in each compartment and in blood. In each fluid, four forms of the agent are distinguished: unionized dissolved in water ("standard" form), ionized dissolved in water, unionized dissolved in lipid, and bound to protein. Equations define the equilibrium between these four forms in any one fluid and between blood and tissue. After changing two of the more uncertain numbers in the quantification for pethidine, good agreement was obtained between computed and published venous concentrations after single i.v. and i.m. injections, continuous i.v. infusions and repeated i.m. injections. The model can be used to make a wide variety of "what if" predictions.
Tobramycin is a new aminoglycoside antibiotic with activity against a wide range of bacteria. More than 90% of coliform organisms and Pseudomonas were susceptible in vitro to 5\g=m\g/ml of tobramycin. Pharmacokinetic properties of tobramycin in neonates are similar to those of gentamicin. Peak levels of 4\g=m\gto 6\g=m\g/mlare achieved in serum after a dose of 2.0 mg/kg; it can be given every 12 hours for up to ten days without accumulation. Serum half-life values were inversely related to birth weights and creatinine clearances. It is suggested that tobramycin be used only for the treatment of neonatal infections caused by tobramycin-susceptible gram-negative organisms resistant to both kanamycin and gentamicin. Studies of clinical efficacy and toxicity in neonates are necessary before the drug can be recommended for routine use.Experi ence over the past two dec¬ ades has shown that gram-nega¬ tive organisms may develop signifi¬ cant resistance to an aminoglycoside antibiotic within a few years of its routine use in a newborn nursery.This was observed with streptomycin in the early 1960s and in the past three years with kanamycin.1 With the increasing use of gentamicin in neonatal units, it is possible that emergence of gentamicin-resistant bacteria will occur. Accordingly, anti¬ biotics with similar antimicrobial spectra that do not demonstrate cross-resistance with the older aminoglycosides should be developed and studied in newborn infants.Tobramycin is a new aminoglyco¬ side antibiotic similar in structure to kanamycin and gentamicin. The com¬ mon pathogenic coliform organisms and Pseudomonas are susceptible to tobramycin.2 3 Furthermore, the drug is resistant to some of the bacterial enzymes (R-factors) that inactivate gentamicin.4 The pharmacokinetic properties of tobramycin in adults are similar to those of gentamicin.5It is likely that tobramycin will be licensed in the near future, and be¬ cause of its potential use in the treat¬ ment of neonatal bacterial infections caused by organisms resistant to kana¬ mycin and gentamicin, the antimicro¬ bial activity against gram-negative bacteria isolated from neonates and the clinical pharmacology of tobramy¬ cin in full-term and premature in¬ fants were studied. The clinical impli¬ cations of these data are presented as a guide for pediatricians faced with the dilemma of selecting antibiotic therapy for infections caused by bac¬ teria which are resistant to the cur¬ rently available drugs. Materials and MethodsSusceptibility Studies.-The susceptibili¬ ties of 724 gram-negative organisms iso¬ lated from blood, cerebrospinal fluid, and urine of sick neonates and from stool cul¬ tures of normal babies were determined by agar plate dilution using a multiple inocu¬ lating apparatus.6' Serial two-fold dilu¬ tions of laboratory standards of tobramy¬ cin (l,000mg/ml-Lilly Laboratories) and gentamicin (586|iig/ml-Schering Corpora¬ tion) were incorporated into oxoid agar.The inoculum applied was 105 bacteria/ml. The lowest concentration of antibiotic in¬ hibiting visible ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.